Mauna Loa measurements of carbon dioxide. From http://keelingcurve.ucsd.edu/

The last time atmospheric CO₂ was at 400 parts per million was during the ancient Pliocene Era, three to five million years ago, and humans didn’t exist.

• Global average temperatures were 3 to 4 degrees C warmer than today (5.4 to 7.2 degrees F).
• Polar temperatures were as much as 10 degrees C warmer than today (18 degrees F).
• The Arctic was ice free.
• Sea level was between five and 40 meters higher (16 to 130 feet) than today.
• Coral reefs suffered mass die-offs.

And much more: As Robert Monroe notes: “The extreme speed at which carbon dioxide concentrations are increasing is unprecedented. An increase of 10 parts per million might have needed 1,000 years or more to come to pass during ancient climate change events. Now the planet is poised to reach the 1,000 ppm level in only 100 years if emissions trajectories remain at their present level.”

Here are some scientific links for those wanting to know more:

• Trends in atmospheric carbon dioxide: http://www.esrl.noaa.gov/gmd/ccgg/trends/mlo.html
• Details on the Mauna Loa Observatory, and the “Keeling Curve:” http://keelingcurve.ucsd.edu/
• Robert Monroe discusses what the Pliocene Earth looked like, here: http://keelingcurve.ucsd.edu/what-does-400-ppm-look-like/
• Haywood et al. also review what we know about the Pliocene:  Haywood et al. 2009. “Introduction. Pliocene climate, processes and problems. Phil. Trans. R. Soc. A. Vol. 367, No. 1886, pp. 3-17. 13 January 2009 doi:10.1098/rsta.2008.0205 http://rsta.royalsocietypublishing.org/content/367/1886/3.full.
• B. Schneider and R. Schneider. 2010. Palaeoclimate: Global warmth with little extra CO₂. Nature Geoscience Vol. 3, pp. 6-7. 20 December 2009. doi:10.1038/ngeo736. http://www.nature.com/ngeo/journal/v3/n1/pdf/ngeo736.pdf
• In fact, here’s an entire set of papers discussing the Pliocene, current and past CO₂ levels and conditions, and more: http://www.nature.com/search/executeSearch?sp-q-1=&sp-q=High+Earth-system+climate+sensitivity+determined+from+Pliocene+carbon+dioxide+concentrations&sp-p=all&sp-c=25&sp-m=0&sp-s=&sp-a=sp1001702d&sp-sfvl-field=subject%7Cujournal&sp-x-1=ujournal&sp-p-1=phra

Yet every drop of water on the river is accounted for, used, reused, and transpired away, and today, no water reaches the Colorado River delta in an average year. Quite simply, demands on the river exceed the river’s average supply, and this problem is projected to get worse as populations continue to grow and as climate changes increase temperatures and reduce runoff.

Today, irrigated agriculture consumes more than 70% of the water supply within the Colorado River basin. For the first time, new research from the Pacific Institute presents comprehensive data on the extent of irrigated agriculture throughout the seven Colorado River basin states and two additional states in Mexico, the types of crops grown, and the amount of water used to grow these crops.

More importantly, the new report – Water to Supply the Land: Irrigated Agriculture in the Colorado River Basin – explores the potential for agricultural management strategies to save water, without remove agricultural land from production – through changes in irrigation technology, management strategies, and cropping patterns.

Click here to visit the interactive map of Colorado River basin agriculture, showing federal and state agency information on the amount of irrigated and total harvested acreage in the basin by county, and total reported water use as reported by USGS.

The report shows that more than 90% of pasture and cropland in the 256,000-square-mile Colorado River Basin requires irrigation, with about 60% of the irrigated acreage devoted to pasture, alfalfa, and other forage crops used to feed cattle and horses. These forage crops consume about 5 million acre-feet per year, equivalent to a third of the river’s annual flow.

Innovative irrigation techniques, which many farmers around the world are already using, can help ensure continued agricultural production, while cutting water demands, even in the fact of the growing threat of climate change.

The new study evaluates specific water-efficiency strategies, including regulated deficit irrigation, crop shifting, and advanced irrigation technologies. The Institute’s results show considerable water savings are possible. For example, almost a million acre-feet of water may be saved cheaply and quickly by irrigating alfalfa less often (a practice known as “regulated deficit irrigation”), at an estimated base cost of approximately $81 per acre-foot.

Other scenarios, such as shifting to less water-intensive crops, also yield impressive water savings at relatively low costs and without reducing the total amount of irrigated acreage in the basin. For example, replacing about 10% of the basin’s irrigated alfalfa acreage with cotton and wheat could save about 250,000 acre-feet of consumptive water use each year, with estimated base costs of less than $40 per acre-foot. Total reductions in water withdrawals and applied water would be even greater.

Lead author of the study, Michael Cohen, observed

“We know water supply and demand don’t match up and it will get worse going forward. We know there is much that can be done; the question is how much and where, and how to get there. This analysis improves understanding of crop acreages and water use in the basin and offers a set of plausible scenarios in which some of the water currently devoted to irrigation could be conserved and used for other purposes – without taking agricultural land out of production.”

Dr. Juliet Christian-Smith, a report co-author, observed that the water management techniques proposed in the study are proven. She says that if efforts are made to expand use of them in the western U.S. it

“could generate significant consumptive use water savings that could be transferred to other users. This report considers different alternative futures and it is important to develop the right incentives to encourage more efficient water use as the gap between water supply and demand grows.”

It is time to get serious about returning the Colorado River basin to even a semblance of hydrologic balance. This report shows how to start.

Download the full report (pdf).

Download the Executive Summary (pdf).

Download the interactive map.

One answer: impose a tax on bottled water.

Fewer than 1 in 3 of all PET bottles are recycled, though most could be. [The bottled water industry claims that a higher percentage of water bottles are recycled (still under 39%), but there is no way to independently verify those data or the methods used to determine them. I asked NAPCOR for their analysis and report on plastic-water-bottle recycling, but they replied “We don't release the adjunct report to the public” since it was prepared for the bottled water industry.] Even so, accepting the optimistic estimate still means that billions and billions of plastic water bottles are sold and thrown away into garbage every year.

More and more municipalities are considering specialty taxes for problematic goods. We’ve long had special taxes on tobacco and alcohol and other dangerous, luxury, or non-essential items, and the funds raised by these taxes sometimes generate revenue used to educate consumers about healthier alternatives. In particular, such taxes can be legal and effective ways of trying to recover some of the additional damages and expenses imposed on cities by bottled water consumption, waste collection, and landfilling. The town of Concord, Massachusetts even banned single bottle sales of bottled water, though most towns don’t go this far.

Opposition to such taxes from the industries targeted can be fierce. Lobbyists, money, and political pressure pour in whenever they are proposed. As one might expect, the bottled water industry lobby group (the International Bottled Water Association), formally opposes taxes on bottled water: “IBWA opposes all taxes, surcharges, fees, and levies specifically targeted against bottled water.” [I expect to see comments on this blog post from them, below.] Part of their argument is that it would reduce the amount of bottled water sold, and thus be a smaller part of city revenues than original expected. This first effect is, of course, precisely the point of imposing selective “sin” taxes on goods and services we might want to limit, or to recover the costs of the damages imposed on society by those goods and services.

Perhaps the best example is the City of Chicago Bottled Water Tax. As of January 1, 2008 the City enacted a tax of $0.05 per bottle of water, defined as “all water which is sealed in bottles offered for sale for human consumption. The term does not include any beverage defined as a ‘soft drink’ under Section 3-45-020 of the Chicago Soft Drink Tax Ordinance, Chapter 3-45 of this Code.” (Chicago does have other taxes that apply to some soft-drink sales.)

In the first five years of this tax (during which time the bottled water industry sued unsuccessfully in an attempt to declare the tax invalid), the City of Chicago raised over $38 million dollars on the sales of 763 million bottles of water (see Figure 1, based on data provided to me by the Chicago Department of Finance).

Revenue from Chicago’s Bottled Water Tax from 2008 to 2012. Source: Chicago Department of Finance.
Prepared by Peter Gleick (2013).

This seems like a successful experiment. Other cities might consider something similar.

[Peter Gleick is author of “Bottled and Sold: The Story Behind Our Obsession with Bottled Water” published in 2010 by Island Press, Washington DC, available from Amazon or Island Press or your local bookstore.]

Thirty-six years ago, this industry didn’t exist. Americans drank fewer than two gallons of bottled water per year, and almost all of that was in the form of water from big office coolers. Figure 1 shows the dramatic exponential growth in bottled water sales over this period. There was a slight downturn in 2008 and 2009, attributed in part to a growing public campaign against bottled water and in part to the severe recession, but sales have resumed their upward climb as companies cut the price of bottles and launched an even more aggressive media and advertising blitz.

Bottled water sales per person in the United States, from 1976 to 2012. Data are from the Beverage Marketing Corporation. Graph by Peter Gleick.

Despite having one of the best municipal tap water systems in the world, American consumers are flocking to commercial bottled water, which costs thousands of times more per gallon. Why? Four reasons:

• First, we have been bombarded with advertisements that claim that our tap water is unsafe, or that bottled water is safer, healthier, and more hip, often with celebrity endorsements. (Thanks a lot, Jennifer.)
• Second, public drinking water fountains have become increasingly hard to find. And the ones that exist are not being adequately maintained by our communities.
• Third, people are increasingly fearful of our tap water, hearing stories about contamination, new chemicals that our treatment systems aren’t designed to remove, or occasional failures of infrastructure that isn’t being adequately maintained or improved.
• Fourth, some people don’t like the taste of their tap water, or think they don’t.

Some people, including the bottled water industry, argue that drinking bottled water is better than drinking soft drinks. I agree. But that’s not what’s happening. The vast increase in bottled water sales have largely come at the expense of tap water, not soft drinks. And even if we pushed (as we should) to replace carbonated soft drinks with water, it should be tap water, not expensive bottled water.

This industry has very successfully turned a public resource into a private commodity. Sales of bottled water now are close to $12 billion a year, and in fact, total expenditures are far larger if you include the cost to consumers. (The sale figures don’t include retail mark-up or total consumer expenditures, I believe.)

But the true costs are even higher. 60 to 70% of all the plastic bottles sold – billions and billions of them – are never recycled, but end up in our garbage.  The Pacific Institute has calculated that the equivalent of 17 million barrels of oil are used to make the plastic in these bottles each year (here is a link to a .pdf of the peer-reviewed scientific paper), not including the additional energy required to drive the bottles around, power the refrigerators that cool them, or deal with the wastes. Some local groundwater depletion also occurs around big bottled water plants, raising concern in local communities in Maine, Michigan, California, Florida, and elsewhere.

We need action on this, including:

Efforts to upgrade and improve our tap water systems. Overall the U.S. has a great system; but it could and should be even better, with new technology to remove new contaminants, improvements to old pipe and distribution systems, better monitoring, and special assistance in rural areas dependent on vulnerable groundwater wells.

Education to consumers about the quality of our tap water, and the true environmental and economic costs of bottled water.

Better comprehensive independent monitoring and enforcement (and strengthening) of bottled water standards, which are not the same as tap water standards, and not as strong in several areas.

Better labeling of bottled water, to provide information on quality, the water source, and the elimination of misleading names and descriptions.

More aggressive and comprehensive plastic recycling: states with stronger recycling laws collect and recycle more plastic. And all bottlers should be required to use some fraction of recycled plastic content.

Improvements in access to drinking water fountains. The Pacific Institute has a beta-version of an Android app (free) that maps water fountains (www.wetap.org) using an open-access database, but this is just a first step to what is needed – a comprehensive dataset of all public water fountains, the ability of any member of the public to add information on fountains (working/broken? clean/dirty?), and pressure to build new fountains where they don’t exist.

And finally, take individual actions: start carrying around a reusable, refillable bottle, if you can’t go from point A to point B without water. Support improvements in your tap water system. Demand better labeling and transparent information from bottled water companies. You’ll save money, reduce your environmental footprint, and help drive sales of bottled water back down.

[Peter Gleick is author of “Bottled and Sold: The Story Behind Our Obsession with Bottled Water” published in 2010 by Island Press, Washington DC, available from Amazon or Island Press or your local bookstore.]

Today is Earth Day, when we celebrate the planet, and in particular the functioning ecosystem that supports all life, including our own. In recognition of Earth Day, here is a short piece about bottled water in the United States and most developed countries, with some basic facts that should help any readers still in doubt about the downsides of that industry.

The Money

Bottled water, served in single-serve plastic (PET) bottles, is staggeringly expensive. You don’t think about it when you only pay a couple of dollars for each little bottle, but over time, and compared to our high-quality tap water, bottled water is a couple of thousand times more expensive. Here’s a graph:

The typical cost of bottled water versus tap water. (Source: P.Gleick 2013)

The Quality

There is no reason to believe that bottled water quality is any better than tap water quality despite the advertising hype and public perception. The laws that protect water quality for both are similar (but not identical – some bottled water regulations are weaker than tap water regulations). But enforcement and monitoring is far less consistent, less independent, and weaker for bottled water (partly regulated by the Food and Drug Administration as a food product) than tap water (regulated by the Environmental Protection Agency). Here is a list of over 100 bottled water “recalls” for contamination (pdf), and it is likely that many others have never been discovered or publicized. My favorite was the recall due to contamination with “crickets.” Really.

The Environmental Impact

The environmental impacts of bottled water are largely foisted on the public and our ecosystems in the form of large amounts of energy to produce the plastic and large amounts of plastic thrown away into our environment. It takes the equivalent of 17 million barrels of oil every year to make the PET water bottles we consume in the United States, and even more energy to move it, store it, and chill it (the IBWA pretends this is a “myth” but here is the link to the scientific paper (pdf) that discusses the massive energy requirement of bottled water). Most PET bottles are not recycled; most (more than 60%) are dumped in landfills or by the side of the roads.

Around 45% of all bottled water comes from local groundwater sources (sometimes labeled as “spring” water). In some regions, these aquifers have been overpumped, with adverse consequences for local wells and streams.

But the rest (around 55%) of all bottled water is simply taken from local municipal tap water systems. Sometimes it receives additional processing, but that tap water originally met all federal water quality standards, and cost a tiny fraction of what the bottled water industry subsequently charges for turning a public resource into a private commodity.

So, one thing you can do for the Earth today and every day? Cut back on your purchases of bottled water. Start to carry a refillable bottle around if you feel the need to rehydrate during the day. More and more drinking water fountains are being designed to fill bottles. Here is a new “GlobalTap” fountain at the San Francisco Airport.

GlobalTap Fountain at the San Francisco Airport. (Source: P.Gleick 2013)

And to help you find public drinking water? Here is an Android app (WeTap) that lets you find nearby drinking water fountains or add new ones to a global, open source database. Information on WeTap is here.

Far more information on the history, science, and consequences of bottled water can be found in the book “Bottled and Sold: The Story Behind our Obsession with Bottled Water” (Island Press, Washington DC).

Here are three more, along with a bonus fourth, all with a theme of exponential growth – the powerful force that is behind much of the concern about climate change and many other environmental and social challenges. Figures like these are increasingly called “hockey stick” curves, after the work of Professor Michael Mann and others in the climate community, but such rapid exponential changes, which often signify problems (unless your bank balance looks like this) are common in other scientific fields as well.

First: a root of the problem. Global population. Figure 1 shows the world’s population from 1300 to the modern era. Today’s population exceeds 7 billion.

Figure 2 from the 2013 US national climate assessment shows two thousand years of atmospheric concentrations for carbon dioxide, methane, and nitrous oxide: three of the most important and dangerous greenhouse gases.

Figure 3 shows over 10,000 years of carbon dioxide concentrations with measurements taken from ice cores (and a clear discussion at the website of Skeptical Science), and most recently from the Mauna Loa station (those instrumental data were shown, in more detail, in my April 2^nd post).

Figure 4 is a clear, albeit disturbing graph that includes recent key findings on ancient temperatures reconstructed by the paleoclimate community for the past 20,000 years, plus the most recent instrumental record, plus projections from state-of-the-art climate models, showing how the world is racing into uncharted waters.

More “significant figures” to come.

Figure 1. Global population over the past 800 or so years. Today’s population is over 7 billion, and growing.

Figure 2. 2000 years of atmospheric concentrations of major greenhouse gases (CO2, methane, nitrous oxide), from http://www.globalchange.gov/HighResImages/1-Global-pg-14.jpg.

Figure 3. 10,000 years of atmospheric carbon dioxide concentrations from paleoclimatic records, and recent observations. http://www.skepticalscience.com/co2-measurements-uncertainty.htm

Figure 4. 20,000 years of global estimated temperature, from paleoclimate reconstructions, recent observations, and model projections. http://tamino.wordpress.com/2013/03/22/global-temperature-change-the-big-picture/.

The first is the atmospheric concentration of carbon dioxide, measured at the Mauna Loa observatory in Hawaii. It shows the little ups and downs in concentration that varies with the seasons, but also the inexorable rise in this powerful greenhouse gas. There are now thousands of stations measuring these gases.

The second is the deviation from global average temperatures over the past 130 years. It also shows the natural variability (ups and downs) of temperature, together with the disturbing rapid rise that scientists say is due to human factors (especially, the rise in greenhouse gases shown in Figure 1). The temperature data come from NASA’s GHCN-M version 3.1.0 dataset. Again, there are other global datasets. They all show the same thing.

The third graph is the volume of ice in the Arctic (extent and depth together give you total ice volume), showing the rapid decline is the Arctic ice cap — far more rapid than even conservative scientists expected (“conservative” in the non-political sense). These data come from the PIOMAS Polar Science Center.

Read ‘em and weep.

[UPDATE NOTE: On April 4, I updated the second graphic with the latest (through 2012) combined land/ocean temperature anomalies. The overall trend is unchanged. I would also note, there are other datasets from research groups around the world, all of which show the same trends. Thanks to Richard (see comments below) for calling attention to the newest data.) The data come from: ftp://ftp.ncdc.noaa.gov/pub/data/anomalies/monthly.land_ocean.90S.90N.df_1901-2000mean.dat.

Atmospheric CO2 measured at Mauna Loa, Hawaii.

Updated Global (combined surface and ocean) temperatures from NASA Deviations from the average global temperature since 1880. Data from NASA . http://www.ncdc.noaa.gov/cmb-faq/anomalies.php#anomalies. Thanks to Richard to asking for the most recent data.

Arctic sea ice volume from the PIOMAS dataset.

It might seem strange to some that a water wonk like me spends considerable time in the desert. I’ve tried to go down to the vast Southern California desert for some time every year, typically in the spring when the winter cold is receding and the days are getting longer and there is a chance of some of the dramatic wildflower blooms that the sparse desert rains can produce. The skies at night are phenomenal; the landscapes primitive, and the wildlife raw. There is no better place to see how nature adapts to extremes and to get away, even briefly, from the day-to-day.

And there is no better place than the desert if you truly want to understand water and the role it plays in our personal lives, where limits on water define everything you see and do.

I’ve just returned from my annual pilgrimage. I go with family and sometimes friends. We car-camp, but have favorite spots that are very isolated off the main roads in different locations around Death Valley, the Mohave preserves, Anza Borrego, and elsewhere. I won’t say where (we desert rats always have our favorite remote special places), but on a typical three or four day trip, we may see only two or three other groups of people. [Here’s a hint: I took this photo at dusk, facing west.]

Somewhere in the California desert.Photo: P. Gleick, March 28, 2013

Modern conveniences have made desert camping easy. Four-wheeled or all-wheel drive vehicles are common and provide reliable access to remote areas. There are excellent maps. Comfortable camping equipment makes sleeping under the stars a wonderful experience. You can carry more water than if you were backpacking (remember, water weighs eight pounds per gallon). And we cook and eat magnificently (Freeze-dried stuff? Never. We prepare gourmet food on one or two burners.)

The limit is always water. When we run out of it, we must leave or move and find a place to refill our water bottles.

This year, there were three of us. We had a total of around seven gallons of water, plus perhaps another gallon of drinks (fruit juice, beer, wine) in a cooler with our food, plus whatever water was in the food itself.

The water itself had to serve for cooking, drinking, and cleaning. And it lasted three nights and parts of four days for three people – nearly three full days measured in hours.

We used it for drinking: to fill our water bottles that accompanied us on our hikes through washes and canyons and across a long valley to an old mining site and desert oasis. Perhaps four gallons over the time we were out.

We used it for washing and rinsing dishes and pots after cooking. Each major meal (three dinners and three cooked breakfasts; lunches were sandwiches, fruit, cookies) could be cleaned up with around a quart of water – say another two gallons. [As an example of how opportunistic desert life is when a source of moisture appears, here is a photo of what showed up within a minute or two of cutting open an orange.]

White-lined sphinx moth. Photo: P. Gleick 2013.

Not a lot of personal washing occurred: perhaps another gallon over the nine person-days of the trip.

And that’s it. We left the desert with only a quart or two of water remaining. In a few hours we were sitting in a restaurant drinking 20-ounce lemonades and milk shakes.

We also left the desert with, of course, a substantial water debt: more water went to showers and to wash our clothes when we got home. A lot of it. More water went to wash the dishes, pans, and utensils so they will be clean for the next time we use them. Sustaining the low level of water used in the desert involves, in the end, deprivation and limits and compromises of many different kinds, as billions of people know.

So it is good to be reminded, every now and again, of the value of water, of how precious it is, and how much less one can use when necessary. I am lucky to live in a society where we don’t have to get by on a few gallons per day, we don’t have to consider the water cost of every action, clean and incredibly cheap water comes out of our taps, and the struggle for water doesn’t define our lives. If only this were so for the billions of people who do not have the water riches we do.

 Peter Gleick

• Stop taking your tap water for granted. Go to your tap, draw a glass of water, and drink it. Then remember that nearly a billion people still do not have reliable access to safe, affordable tap water and cannot do what you’ve just done.
• Stop taking your toilet for granted. Nearly 2.5 billion people (more people than lived on the planet in the 1930s) don’t have safe sanitation.
• Do you know anyone who had cholera, or typhoid, or dysentery? Most likely not. Yet just a few generations ago, some of your ancestors certainly died from one of these diseases – associated with the lack of safe water and sanitation.
• That food you’re eating? It took a lot of water to produce it. Around 80 percent of all of the freshwater humans use goes to grow food. The rest is split among home, industrial, and commercial uses.
• Those clothes you’re wearing? It took a lot of water to produce them as well, whether you’re wearing cotton or polyester. A cotton t-shirt involves cotton that may be grown in India, woven into fabric and dyed in China, finished in Mexico, and sold in the U.S. Thus the “water footprint” of that shirt could involve water from around the world. [Here is a report we just released on California’s water footprint; and here is a more general link to water footprints at the Water Footprint Network.]
• Turn on your computer or light? It took water – yes, water – to produce that energy. Depending on the energy source, it might have taken a lot of water. But renewable energy sources typically (not always) require far less water for every kilowatt-hour of energy produced.
• We read all the time about the damages we’re doing to the environment, and especially, the species of that we’re driving to extinction. But most of them aren’t furry mammals or photogenic megafauna. The majority of species threatened with extinction are aquatic – threatened by human use and contamination of water. More than one-third of threatened and endangered species in the U.S. live only in wetlands, according to the U.S. EPA.
• Violent conflicts happen for many reasons: economic, religious, ideological, geographical, ethnic, and more. But a growing number of conflicts are linked to disputes over water resources. (You can find a comprehensive list at The Water Conflict Chronology that is maintained by the Pacific Institute.)
• “There is compelling, comprehensive, and consistent objective evidence that humans are changing the climate in ways that threaten our societies and the ecosystems on which we depend.” Among other things, this evidence includes rapidly rising temperatures, dramatic losses of the Arctic ice cap, disappearing glaciers, ocean acidification, ecosystem shifts, and rising seas. Some of the most severe impacts of climate changes will be on water resources – both supply and demand.
• Because climate changes are already occurring, weather events, including extreme events, are increasingly influenced by them. Scientists have been clear: expect to see more extremes of heat, extended drought, and water shortages in many places. This year, keep a concerned eye on the water situation in the central and southwestern United States.

Some Good News

• The assumption that demand for water must go up, up, up with population and economic growth is wrong. The U.S. (and many other countries) uses less water today than 35 years ago and far less per person. This is due to a combination of improved efficiency and changes in our economy. Figure 1 shows this trend for the U.S., and it is great news.

Total U.S. water withdrawals peaked and then declined after the late 1970s, even while population and GNP have continued growing. Source: Gleick 2003 Annual Reviews.

• There is tremendous additional potential for improving efficiency and productivity of water use. We can do far more with less water in every sector from agriculture to industry to our homes.
• It is possible to restore damaged natural ecosystems if we restore some semblance of natural water stocks and flows. Removing hundreds of old, unsafe, harmful dams has led to improved safety, restored fisheries, and healthier ecosystems. In 2012, 62 dams were removed in the United States alone.
• There is a formal “human right to water” declared by the United Nations General Assembly and Human Rights Council, and while by itself this will not magically solve water problems, it acknowledges the importance of meeting basic needs and lays out the responsibilities of nations to more actively address water and sanitation needs for their poorest populations.
• There are wonderful non-governmental, international, and community organizations of all kinds working on water problems, from research (such as my own Pacific Institute) to on-the-ground assistance. (Here is one list; here is another; commenters should feel free to add more!).

So happy World Water Day. Don’t take your water for granted – and take action.

Peter Gleick

In response, in the past few months, there has been a last-gasp effort (see, for example,  here and here) on the part of the ever-shrinking group of hard-core climate deniers to confuse the public and especially our elected officials. Given this continuing profusion of false and misleading information, and given the growing debate about climate policy and whether to pursue projects such as the Keystone XL pipeline, I repost the Letter here.

—

Climate Change and the Integrity of Science

(Science Magazine, May 7, 2010)

We are deeply disturbed by the recent escalation of political assaults on scientists in general and on climate scientists in particular. All citizens should understand some basic scientific facts. There is always some uncertainty associated with scientific conclusions; science never absolutely “proves” anything. When someone says that society should wait until scientists are absolutely “certain” before taking any action, it is the same as saying society “should never take action.” For a problem as potentially catastrophic as climate change, taking no action poses a dangerous risk for our planet.

Scientific conclusions derive from an understanding of basic laws supported by laboratory experiments, observations of nature, and mathematical and computer modeling. Like all human beings, scientists make mistakes, but the scientific process is designed to find and correct them. This process is inherently adversarial – scientists build reputations and gain recognition not only for supporting conventional wisdom, but even more so for demonstrating that the scientific consensus is wrong and that there is a better explanation. That’s what Galileo, Pasteur, Darwin, and Einstein did. But when some conclusions have been thoroughly and deeply tested, questioned, and examined, they gain the status of “well-established theories” and are often spoken of as “facts.”

For instance, there is compelling scientific evidence that our planet is about 4.5 billion years old (the theory of the origin of Earth), that our universe was born from a single event about 14 billion years ago (the Big Bang theory), and that today’s organisms evolved from ones living in the past (the theory of evolution). Even as these are overwhelmingly accepted by the scientific community, fame still awaits anyone who could show these theories to be wrong. Climate change now falls into this category: there is compelling, comprehensive, and consistent objective evidence that humans are changing the climate in ways that threaten our societies and the ecosystems on which we depend.

Many recent assaults on climate science and, more disturbingly, on climate scientists by climate change deniers, are typically driven by special interests or dogma, not by an honest effort to provide an alternative theory that credibly satisfies the evidence. The Intergovernmental Panel on Climate Change (IPCC) and other scientific assessments of climate change, which involve thousands of scientists producing massive and comprehensive reports, have, quite expectedly and normally, made some mistakes. When errors are pointed out, they are corrected. But there is nothing remotely identified in the recent events that changes the fundamental conclusions about climate change:

1. The planet is warming due to increased concentrations of heat-trapping gases in our atmosphere. A snowy winter in Washington does not alter this fact.
2. Most of the increase in the concentration of these gases over the last century is due to human activities, especially the burning of fossil fuels and deforestation.
3. Natural causes always play a role in changing Earth’s climate, but are now being overwhelmed by human-induced changes.
4. Warming the planet will cause many other climatic patterns to change at speeds unprecedented in modern times, including increasing rates of sea-level rise and alterations in the hydrologic cycle. Rising concentrations of carbon dioxide are making the oceans more acidic.
5. The combination of these complex climate changes threaten coastal communities and cities, our food and water supplies, marine and freshwater ecosystems, forests, high mountain environments, and far more.

Much more can be, and has been, said by the world’s scientific societies, national academies, and individuals, but these conclusions should be enough to indicate why scientists are concerned about what future generations will face from business-as-usual practices. We urge our policymakers and the public to move forward immediately to address the causes of climate change, including the unrestrained burning of fossil fuels.

We also call for an end to McCarthy-like threats of criminal prosecution against our colleagues based on innuendo and guilt by association, the harassment of scientists by politicians seeking distractions to avoid taking action, and the outright lies being spread about them. Society has two choices: we can ignore the science and hide our heads in the sand and hope we are lucky, or we can act in the public interest to reduce the threat of global climate change quickly and substantively. The good news is that smart and effective actions are possible. But delay must not be an option.

Signed
[255 members of the U.S. National Academy of Sciences]
[The signers are all members of the U.S. National Academy of Science, but are not speaking on its behalf. Names are in alphabetical order, except for Dr. Peter Gleick, the corresponding author.]

Gleick, Peter H (corresponding author)

Adams, Robert McCormick
Amasino, Richard M
Anders, Edward
Anderson, David J
Anderson, Wyatt W
Anselin, Luc E
Arroyo, Mary Kalin
Asfaw, Berhane
Ayala, Francisco J
Bax, Adriaan
Bebbington, Anthony J
Bell, Gordon
Bennett, Michael V L
Bennetzen, Jeffrey L
Berenbaum, May R
Berlin, Overton Brent
Bjorkman, Pamela J
Blackburn, Elizabeth
Blamont, Jacques E
Botchan, Michael R
Boyer, John S
Boyle, Ed A
Branton, Daniel
Briggs, Steven P
Briggs, Winslow R
Brill, Winston J
Britten, Roy J
Broecker, Wallace S
Brown, James H
Brown, Patrick O
Brunger, Axel T
Cairns, Jr John
Canfield, Donald E
Carpenter, Stephen R
Carrington, James C
Cashmore, Anthony R
Castilla, Juan Carlos
Cazenave, Anny
Chapin, III F, Stuart
Ciechanover, Aaron J
Clapham, David E
Clark, William C
Clayton, Robert N
Coe, Michael D
Conwell, Esther M
Cowling, Ellis B
Cowling, Richard M
Cox, Charles S
Croteau, Rodney B
Crothers, Donald M
Crutzen, Paul J
Daily, Gretchen C
Dalrymple, Brent G
Dangl, Jeffrey L
Darst, Seth A
Davies, David R
Davis, Margaret B
De Camilli, Pietro V
Dean, Caroline
DeFries, Ruth S
Deisenhofer, Johann
Delmer, Deborah P
DeLong, Edward F
DeRosier, David J
Diener, Theodor O
Dirzo, Rodolfo
Dixon, Jack E
Donoghue, Michael
Doolittle, Russell F
Dunne, Thomas
Ehrlich, Paul R
Eisenstadt, Shmuel N
Eisner, Thomas
Emanuel, Kerry A
Englander, Walter S
Ernst, W, G
Falkowski, Paul G
Feher, George
Ferejohn, John A
Fersht, Sir Alan
Fischer, Edmond H
Fischer, Robert
Flannery, Kent V
Frank, Joachim
Frey, Perry A
Fridovich, Irwin
Frieden, Carl
Futuyma, Douglas J
Gardner, Wilford R
Garrett, Christopher J R
Gilbert, Walter
Gleick, Peter H
Goldberg, Robert B
Goodenough, Ward H
Goodman, Corey S
Goodman, Morris
Greengard, Paul
Hake, Sarah
Hammel, Gene
Hanson, Susan
Harrison, Stephen C
Hart, Stanley R
Hartl, Daniel L
Haselkorn, Robert
Hawkes, Kristen
Hayes, John M
Hille, Bertil
Hökfelt, Tomas
House, James S
Hout, Michael
Hunten, Donald M
Izquierdo, Ivan A
Jagendorf, André T
Janzen, Daniel H
Jeanloz, Raymond
Jencks, Christopher S
Jury, William A
Kaback, H Ronald
Kailath, Thomas
Kay, Paul
Kay, Steve A
Kennedy, Donald
Kerr, Allen
Kessler, Ronald C
Khush, Gurdev S
Kieffer, Susan W
Kirch, Patrick V
Kirk, Kent C
Kivelson, Margaret G
Klinman, Judith P
Klug, Sir Aaron
Knopoff, Leon
Kornberg, Sir Hans
Kutzbach, John E
Lagarias, J Clark
Lambeck, Kurt
Landy, Arthur
Langmuir, Charles H
Larkins, Brian A
Le Pichon, Xavier T
Lenski, Richard E
Leopold, Estella B
Levin, Simon A
Levitt, Michael
Likens, Gene E
Lippincott-Schwartz
Lorand, Laszlo
Lovejoy, Owen C
Lynch, Michael
Mabogunje, Akin L
Malone, Thomas F
Manabe, Syukuro
Marcus, Joyce
Massey, Douglas S
McWilliams, Jim C
Medina, Ernesto
Melosh, Jay H
Meltzer, David J
Michener, Charles D
Miles, Edward L,
Mooney, Harold A
Moore, Peter B
Morel, Francois M M
Mosley-Thompson
Moss, Bernard
Munk, Walter H
Myers, Norman
Nair, Balakrish G
Nathans, Jeremy
Nester, Eugene W
Nicoll, Roger A
Novick, Richard P
O’Connell, James F
Olsen, Paul E
Opdyke, Neil D
Oster, George F
Ostrom, Elinor
Pace, Norman R
Paine, Robert T
Palmiter, Richard D
Pedlosky, Joseph
Petsko, Gregory A
Pettengill, Gordon H
Philander, George S
Piperno, Dolores R
Pollard, Thomas D
Price Jr. Buford P
Reichard, Peter A
Reskin, Barbara F
Ricklefs, Robert E
Rivest, Ronald L
Roberts, John D
Romney, Kimball A
Rossmann, Michael G
Russell, David W
Rutter, William J
Sabloff, Jeremy A
Sagdeev, Roald Z
Sahlins, Marshall D
Salmond, Anne
Sanes, Joshua R
Schekman, Randy
Schellnhuber, John
Schindler, David W
Schmitt, Johanna
Schneider, Stephen H
Schramm, Vern L
Sederoff Ronald R
Shatz, Carla J
Sherman, Fred
Sidman, Richard L
Sieh, Kerry, Nanyang
Simons, Elwyn L
Singer, Burton H
Singer, Maxine F
Skyrms, Brian
Sleep, Norman H
Smith, Bruce D
Snyder, Solomon H,
Sokal, Robert R
Spencer, Charles S
Steitz, Thomas A
Strier, Karen B
Südhof, Thomas C
Taylor, Susan S
Terborgh, John
Thomas, David Hurst
Thompson, Lonnie G
Tjian, Robert T
Turner, Monica G
Uyeda, Seiya
Valentine, James W
Valentine, Joan Selverstone
Van Etten, James L
Van Holde, Kensal E
Vaughan, Martha
Verba Sidney
Von Hippel, Peter H
Wake, David B
Walker, Alan
Walker John E
Watson, Bruce E
Watson, Patty Jo
Weigel, Detlef
Wessler, Susan R
West-Eberhard, Mary Jane
White, Tim D
Wilson, William Julius
Wolfenden, Richard V
Wood, John A
Woodwell, George M
Wright, Jr Herbert E
Wu, Carl
Wunsch, Car
Zoback, Mary Lou